xoa slow export

akurzawa

Hi

I've started exporting 3 vms - to be specific - 2 day old snapshots of there vms. Export using fast xcp-ng compression. On the beginning the export was fast (20MB/s is fast?) but later the speed dropped to incredibly slow vales like 200kB/s as seen on screenshot. The server is idle now, 4 vms up.

Any idea why the speed of export dropped that drastically down?

olivierlambert

It has to flow from a host, to XOA then to your browser. Anything that could slow the traffic between could explain. Also, what kind of compression did you use?

akurzawa

It seems that this is impossible for xoa to export 2 o more vm at once

olivierlambert

I'm not sure about this, asking @julien-f or @pdonias about it

akurzawa

I've endless export task :

atlas vm on 2nd server xoa is on 1st, both xcp-ng servers connected to single gb switch thru 4-port lacp connection

cg

Can't say for XOA specific, but let me add: 20 MB/s is slow (even with XS) - on better systems it should rather hit 200 MB/s.

olivierlambert

It's hard to tell slow or not without knowing all the context Using GZIP compression, it's "normal". Then you have network speed between the host and XO, then between XO and the web browser.

"Slow" alone doesn't mean anything!

julien-f

@akurzawa said in xoa slow export:

It seems that this is impossible for xoa to export 2 o more vm at once

Indeed, for the time being, XO limits to 2 concurrent exports on any given pool, this will change in the near future.

julien-f

@akurzawa said in xoa slow export:

I've endless export task

Should not cause any issues and it will automatically be destroyed by the XenAPI after 24 hours.

akurzawa

@julien-f said in xoa slow export:

@akurzawa said in xoa slow export:

I've endless export task

Should not cause any issues and it will automatically be destroyed by the XenAPI after 24 hours.

wow just 24 hours? Do you know that I cannot shotdown the host right now nor my UPS in case of power failure?

julien-f

@akurzawa I'm not sure but restarting xo-server might do the trick as well.

olivierlambert

Toolstack restart will cancel the task.

cg

Did you do any tests with XCP-ng Center? Just to get any numbers.
I have one VM on XS that needs to be exportet regulary, which hits about 800 GB in ~22 hours. It always starts reasonably quick and then becomes slower by time - but 800 vs. 8...

akurzawa

@cg said in xoa slow export:

Did you do any tests with XCP-ng Center? Just to get any numbers.
I have one VM on XS that needs to be exportet regulary, which hits about 800 GB in ~22 hours. It always starts reasonably quick and then becomes slower by time - but 800 vs. 8...

In 90% cases I'm obsrving the sam thing - export either in xoa or xcp-ng center is getting slowe over time... idk whats the reason of that.

cg

As Citrix barely ever gave any insights... maybe @olivierlambert can bring light into that.

olivierlambert

We aren't doing any test with XCP-ng Center because we don't use it at all You can use xe to compare (xe CLI is basically another XAPI client -like XO or XCP-ng Center- which can run on the same host or even elsewhere)

akurzawa

Regardin export from xoa I the highest speed that I've seen was 40MB/s on raid10 setup, xoa and vm on the same host. What could be the reason of that? Host is almost always idle, just very basic workload.

olivierlambert

Export from XOA to where? Your browser, a remote?

akurzawa

Export from xoa, Gb LAN, latest Chrome, Windows

cg

@olivierlambert It's basically the same. I almost only export via scripts/xe.